How should I clean the buckle strap on the Tranzitions?

To clean the buckle strap, place it in a cup of warm water and gently agitate the buckle, pressing the red button several times while in the water. Do not submerge the buckle strap or use soaps, household detergents, or lubricants. Shake out excess water and allow to air dry, repeating as needed until it fastens with a click. (Page 85)